A question. Are all hot chassis sets AC/DC.
I have a little Masteradio with just AC mains written on the back. I see a few identical case models with AC/DC Mains written on the back.

If there is no transformer to impede direct current then, yes, the radio will operate.

I think this is a safer option than running a hot chassis, providing of course that the DC supply is isolated from mains.

The DC fed directly into the power input circuit will presumably be the same as the DC voltage measured at the rectifier output when the set
is operating with AC.

There are some hot chassis tranformerless sets (not Oz radios I hasten to add) that use a capacitor in series with the mains input.

Wow! That would be a rare bird to have in any collection.

This one is a common little british set that I picked up for $10.00. Its in nice condition so I just want to get it going well. I am well aware of the dangers with these sets and will mitigate any possibility of electrocution

If you can source an isolation transformer that is your simplest option.

If I recall correctly (IIRC) Aussie plugs are shaped in such a way that you can't plug it in "backwards". Not like American plugs, with the blades in parallel. And if the Aussie electric code dictates which blade will always be the neutral (and if your outlets are correctly wired!) you should be fairly safe if you connect that neutral directly to the B- bus (or the chassis) without it going through a power switch. That switch should be on the hot line.

That works in an ideal world. The problem is that there is a lot of illegal wiring around and also still plenty of mirror-reverse double adaptors, incorrectly wired flexible cords and even a few old houses that were wired up before electrical licencing was introduced. Such places are getting rarer now as the original owners pass on, these houses are sold and most of them are then renovated.

I am one for advocating that great care be taken around an AC/DC set. An isolation transformer is a must and only work live where absolutely necessary (eg: during testing).

An AC/DC set refurb should not be attempted without prior experience with working on radios. Such a set is not for a first timer.

Sorry Wa2ise, No, No, No.

I always use a isolation transformer.

All of the sockets here have a high probability of being correct; However, there are plug in, non contact devices to check that. I have found a couple wired wrong.

Once you get past the socket that's when the fun starts. Here in Australia we have "Tag & Test". To illustrate a point Brad made I have done this Tag & Test on stuff from the Mens Shed, This has to be done if its to have a hope of being sold, or donated if its surplus.

A lot of the stuff donated "In good Faith" comes from dad's shed after he's fallen off the perch, or has moved to care. I would put a figure of around 10% of this stuff being "Non-compliant" & often downright dangerous.

As has also been noted many transformer less sets will run on DC if its the right voltage and polarised correctly. The AC ones can in the case of America can have live frame if the power is inverted & that easy over there. Here these sets are becoming rare but dodgy wiring can also see them with a live chassis. That can result in Hum.

HV DC is more dangerous than AC as it can lock muscles.

Noted frequently: The bench isolation transformer here is fitted with a "Kill" switch.

If I recall correctly (IIRC) Aussie plugs are shaped in such a way that you can't plug it in "backwards".

That is true about the shape of the plug, however, as has been mentioned, it doesn't guarantee that the power outlet is wired correctly or that the plug itself (if not molded to the cord) has been wired correctly.

I once owned a 1920's Federation house. One of the first things I did was to use a polarity tester to check all of the power points. A few of them had active and neutral reversed, but the worst thing was a paper clip in one of the ceramic fuses. That place was rewired pronto.

I can identify with that. Bought a house & I do not know who wired it & who messed with it, but it took awhile to sort it all out. Too many circuits on the one fuse and the only place I have ever seen a 32A fuse wedge melt.

When the hot water service in the ceiling got tossed for doing damage & failing; was put somewhere sensible so it could do no damage the fuse box was also tossed and the whole system overhauled. That exercise revealed more dodgy stuff as I have noted before. The cable to the shed came up short & was 2.5mm, this was then wired in with a length of 1mm. Very illegal & to top it off there was a J box where one was never allowed to be.

The cause of the 32A issue was a set of rather dangerous hotplates that also got tossed.

No wonder Energy Safe Victoria pre-RCD was suggesting that wiring be inspected, & insulation tested every five years. Some houses still have cloth rubber wiring.